The effects of oxygen enrichment on the mineral texture in sintered ore with the gaseous fuel injection and its operational results were evaluated in the actual plant.
The mineral composition is an important factor affect to sinter strength. The mineral composition of sintered ore consists of Fe₂O₃, Fe₃O₄, and calcium ferrite and so on. Then, the strength of calcium ferrite is highest of all textures. As the results of sintering test with electrical furnace, calcium ferrite ratio in sintered ore increased with an increase of oxygen concentration in the atmosphere. The increase of oxygen concentration makes calcium ferrite to become stabilized.
Gaseous fuel and oxygen injection technology have been installed at Chiba sinter plant since 2014. It was confirmed the expansion of the temperature zone between 1473 K and 1673 K which is proper for sintering reaction to form the calcium ferrite texture by the gaseous fuel and oxygen injection through the actual plant test. Oxygen enrichment shifted ignition position of coke and gaseous fuel to lower temperature side and the proper temperature zone was expanded. These results denoted the same tendency of the laboratory test results. Moreover, the calcium ferrite ratio of sintered ore increased in the actual plant. As these results, the effects of gaseous fuel and oxygen injection technology were confirmed in the actual machine similarly to the laboratory test.